Hydraulic table reciprocating mechanism



Dec. 26, 1944. y Q G, FLYGARE 2,365,811

` HYDRAULIC TABLE RECIPROCATINGVMECHANISM Filed Aug. 21, 1942 70H r '33 'il 94 Haj Mw/"iva ,07 -CAPI. G. FLYGARE Patented Dec. 26, 1944 HYDRAULIC TABLE BECIPROCATING MECHANISM Carl G. Flygare,. Worcester, Mass., assigner to Norton Company, Worcester, Mass., a corporation o! Massachusetts Application August 21, 1942, Serial No. 455,674

4 Claims.

The invention relates to grinding machines, and more particularly to a hydraulically operated table reciprocating mechanism for a grinding machine.

One object of the invention is to provide a simple and thoroughly practical table reciprocating and reversing mechanism. Another object of the invention is to provide a table reciprocating mechanism in which a table actuated reversing valve serves "to cut oi the flow of fluid under pressure in one direction and in which the valve is positively shifted into a reverse position by fluid under pressure.

A further object of the invention is to provide a reversing mechanism with an improved revers` ing valve, comprising a two-part valve one of which slides relativel to the other to4 facilitate reversal thereof by fluid under pressure. Other objects will be in part'obvious or in part pointed out hereinafter.

The-*invention accordingly consists in the features of construction, combinations of elements, and'arrang'ements of parts, as will be exemplified in the structure to be hereinafter described, and the `scope ofthe application of which will be in- .'dicated in the following claims.

In the accompanying drawing, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is` a diagrammatic showing of the hydraulic control system of the improved table traversing and reversing mechanism;

Fig. 2 is a fragmentary vertical sectional view through the reversing lever and associated parts;

Fig. 3 is a sectional view of the reversing valve, showing the position of the valve parts when pressure is applied by starting the fluid pressure Dump;

Fig. 4 is a similar vertical sectional view of the reversing valve, showing the valve parts in position after the reversing lever has initiated a reversing movement thereof;

Fig. 5 is a similar vertical sectional View, showing the reversing valve parts approaching a reverse position;

Fig. 6 is a similar vertical sectional view of the reversing valve showing the reversing valve and the auxiliary pilot valve in position during a normal reversal at the reverse end of the table f stroke; and

supports a longitudinally reciprocable work supporting table II on the usual V-way and flat way (not shown) for a longitudinal reciprocatory movement relative to the base I0. A fluid operated reciprocating mechanism is provided to reciprocate the table II, comprising a uid pressure cylinder I2 which is flxedly supported by -a pair of bracket end caps I3 and I4 flxedly mounted on the under side of the table II. 'I'he cylinder I2 contains a pair of spaced pistons I5 and IB which are connected by a pair of hollow piston rods I1 and I8. respectively, with a pair of hollow brackets I9 and 20, respectivelyl mounted on opposite ends of the base I0.

The base I0' is preferably formed as a box-like structure containing in its lower portion a reservoir 2l for the fluid pressure system.' Fluid is drawn from the reservoir 2| through a, pipe 22 by means of a motor driven fluid pressure pump 23. The pump 23 forces fluid under pressure through a pipe 24 to a table control or reversing valve l25. A variable pressure relief valve 26 is connected in the pipe line 24 to facilitate passing excess fluid under pressure within the system directly through a pipe 21 into the reservoir 2l so as to maintain a substantially uniform operating pressure within the hydraulic system.

The control valve 25 is a piston type valve having two parts which slide relative to each other. A slidably mounted valve stem 23 is provided with spaced valve pistons 29 and 30. A reduced cylindrical portion 3| of the valve stem 28 passes through a central aperture formed in a slidably mounted reversing valve member 32. I'he reversing valve member 32 is provided with spaced integrally formed pistons 33, 34 and 35. In the position of the valve parts as shown in Fig. 1, fluid under pressure passing from the pipe 24 en'- ters a passage 36 in the valve casing and passes through a. port 3l into a valve chamber 38 lo- Acated between the valve pistons 33 and 34 and passes out through a port 39 and a pipe 40 into a chamber 4I formed within the hollow bracket I9 `and passes through the hollow piston rod I1 into a cylinder chamber 42 formed at the lefthand end of the cylinder I2.

In this position of the parts, fluid within a cylinder chamber 43 formed vat the right-hand end of the cylinder I2 may pass through the hollow piston rod I8, through'a chamber 44 formed within the bracket 20, and through a pipe 4l. through a port 4,6, intova valve chamber 41 located between the valve pistons 34 and 35, and passes out through a port 48 and through a pipe 49 to a manually operable start'and stop valve 5I.

The stop and start valve 5| is preferably a combined stop-start and speed control valve and is preferably formed integral with the valve 25 but for the sake of simplicity of illustration, it has been illustrated diagrammatically in Fig. 1 as a separate valve unit. The valve 5| is preferably located in the exhaust side of the system so as to maintain a uniform fluid pressure on the operating side of the main cylinder I2 during the entire reclprocatory stroke of the cylinder l2 relative to the pistons |5 and i6. The valve 5| comprises a valve stem 55 having formed integrally therewith valve pistons 56 and 51. The control valve 5| is arranged so that it may be moved longitudinally from the full line position into a brok en line position. The valve stem 55 is provided with an actuating knob 58 by means of which the valve may be rotarily adjusted. The right-hand end face of the valve piston 51 is formed as an angular plane face. By a rotary adjustment of the valve stem 55, the position of the angular end face of the piston 51 may be adjusted to open or close a V-port 59 to the desired and predetermined extent and serves as a fine adjustment to cut oi more or less f the exhaust of uid from the system, thereby precisely to regulate the reciprocatory speed of the table I.

In order that the valve piston 51 may be maintained in the desired adjusted position during stopping and starting of the table, a serrated portion 60 is formed integral with the valve stem 55. A spring-pressed arrow-pointed plunger 8| is supported by the casing of the valve and is maintained in engagement with the serrated portion 60 so that the valve stem 55 may be moved endwise or axially to stop and start the table movement without changing the speed adjustment thereof.

A manually operable start and stop lever 65 is pivotally supported by a stud 66 which is in turn supported by a projecting boss 61 formed integral with an apron 8B which is in turn xedly supported on the front of the machine base l0. The control lever 65 is provided with a clearance aperture 69 which surrounds a sleeve 10. The sleeve 10 is rotatably supported on the valve stem 55 and is provided with a pair of diametrically opposed grooves 1| which are engaged by a pair of diametrically opposed studs 12 carried by the control lever 65. It will be readily apparent from the foregoing disclosure that when the control lever 65 is positioned as indicated in full lines (Fig. 1), the V-port 59 will be wholly or partially opened, allowing the table to move at the desired speed as governed by the rotary adjustment ofthe valve stem 55.

When it is desired to stop the reciprocatory movement of the table the control lever 65 is shifted in a clockwise direction (Fig. 1) into broken line position 65a. This movement shifts the valve stem 55 together with the valve pistons 56 and 51 toward the right (Fig. 1) into the broken line position so that the valve piston 51 closes the V-port 59, thus cutting oif the exhaust of fluid from the table cylinder I2 to stop th reciprocatory movement of the table v When the throttle valve 5| is in a closed position, it is desirable to provide a suitablebypass whereby fluid may readily pass from the cylinder chamber 42 into the cylinder chamber l 43 and vice versa to facilitate a manual traversing movement of the table A pipe 80 is connected between the port 39 in the valve 25 and the valve 5|. Similarly, a pipe 8| is connected valve 5|. When the valve stem 55 is moved toward the right (Fig. 1) into a table stop position,

v a valve chamber 82 located between the valve pistons 58 and 51 moves into position 82a so that fluid may readily pass between the pipes 80 and 9| to facilitate a free passage of uid between the cylinder chamber 42 andthe cylinder chamber 43 of the table cylinder l2, so that the table may be readily moved longitudinally without the necessity of overcoming duid under pressure within the system.

A manually operable table traverse mechanism may be utilized such as, for example, that shown in the prior United States Patent No. 2,071,677 and may comprise a manually operable hand wheel and a rack and gear mechanism for moving the work supporting table longitudinally. 'This mechanism is not considered to be a part of the present invention and consequently has not been illustrated or described in detail. For further details of the manually operable traversing mechanism, reference may be had to the United States patent above referred to.

A table actuated mechanism is provided for initiating a shifting movement of the reversing valve 25 comprising a reversing lever 85 which is supported on a rock shaft 88. The rock shaft 96 is journalled in a bearing 81 formed in the apron 68. A short downwardly extending lever 88 is flxedly mounted on the inner end of the rock shaft 86. The lever 88 is provided with a stud 89 which engages or rides in'a vertically extending groove 90 formed in the valve stem 28.l 'I'he reversing lever 85 is provided with a rear- |00, located between the valve'piston 29 and the valve -piston 33, which serves to facilitate a shifting movement of the reversing valve 32 in a manner to be hereinafter described. It should be noted that the differential effective areas of the pistons 29 and 33 serve to aid in the reversal of the valve 25. A port |01, in the position of the valve 25 as shown in Fig. 3, connects the valve chamber |00 with a reservoir |02 formed in the valve casing. A port |03 connects iluid under pressure in the valve passage 36 with the valve chamber |00 during the shifting movement thereof.

Similarly, a valve chamber |05 is provided at the other end of the valve 25. The valve chamber |05 is formed between the valve pistons 38 and 35, respectively. It should be noted that a differential effective area is provided between between the port 40 in the valve 25 with the 1I the valve pistons 30 and 35 to facilitate the shifting of the valve parts during reversal of the valve 25. 'I'he valve chamber |05, in the position shown in Fig. 3, is connected by a port |06 with a port |01 and also connects with the valve passage 36. It should be noted that there is a differential piston area between the valve pistons y35 and 30 so that in the position of the valve as shown in Fig, 3, fluid under pressure passing through the pressure pipe 24 into the valve passage 36 will pass through the port |01 into the valve chamber |05 and, due to the differential effective areas of the pistons 35 and 30, the pressure will shift the valve member 32 toward the left into its extreme left-hand end position and also shift the valve piston 30 toward the right into the position illustrated in Fig. 3. A port |08 is provided `which asaltan serves during the shifting of the valve part toward the right to pass fluid from the valve chamber into a reservoir |09 formed at the righthand end of the valve 25.

In order to attain the main object of the invention, the end valve chambers |00 and |05 are provided to supplement the two-part slidable valve so that when the reversing lever is shifted by engagement with one or the other of the table dogs 92 or 03, the table movement will serve to shift the valve parts to cut oif the exhaust of fluid from one side of the table cylinder l2, after which uid under pressure operating through the end chambers |00 and |05 will automatically and positively shift the valve parts into a reverse position by fluid under pressure. When the machine is idle, that is,.when the fluid pressure pump 23 is shut olf, the 'reversing lever 85 assumes either the full line position 85 or the broken line position 85e as shown in Fig. 1.. During the time when the pump 23 is in operation, the lever 85 never assumes positions 85 or 85o but is positioned in broken line positions indicated in Fig. 1 as 85a or 85D. When the pump 23 is started to force fluid under pressure through the-pipe 24 into the valve passage 33, fluid passes through the port |01 into the valve chamber |05 and shifts the valve part 32 into the extreme left-hand end position, after which the fluid pressure acting upon the valve piston 33 shifts the valve stem 2t toward the right into the position indicated in Fig. 3, whichmovement serves to throw the reversing lever 25 into position 85a i Fig. l). Similarly, at the other end of the table stroke, due to the fluid pressure being admitted to the valve chamber 405, the valve parts assume the positions indicated in Fig. '7 with the reversing lever in position 25h.

The operation of the improved table traversing mechanism will be readily apparent from the foregoing disclosure. Assuming the pump 23 to be started, the fluid under pressure as above described enters the valve chamber W5 to shift the valve parts into the positions indicated in Fig. 3 and to shift the reversing lever into position 25a. Assuming the table to be .traveling toward-the left, as indicated by the arrow in Fig. l, this movement continuesluntil the table dog 33 engages the stud 9| on the reversing lever 85 to rock it in a counterclockwise direction. This movementv of the reversing lever 85 shifts the valve stem toward the right (igs.v l, 3 and 4). f

Due to the position of the valve parts, the valve pistons 2 9 and 30 together With the slidably mounted reversing valve member 32 move toward the right under the influence of the moving table until the valve piston 34 closes the port 48 to stop the exhaust of uid from the cylinder chamber 43. The valve in this position is illustrated in Fig. 4. During this shifting movement of the reversing valve, iiuid within the valve chamber |05 may exhaust through the port |08 into the freservoir |09 so thatit does not retard materially valve piston 33 positively and rapidly shifts the 'l5 reversing valve member 32 into its reverse position so that the valve parts assume the position illustrated in Fig. 5. In the position illustrated in Fig. 5,. uid under pressure entering the valve passage 33 passes into the valve chamber 4l 1ocated between thevvalve pistons 34 and 35 and passes out through the port, 46 and the pipe 45 into the passage 44, through the Vhollow piston rod I8, into the cylinder chamber 43 to move the cylinder I2 and the table toward the right. During the movement of the table towardthe right, fluid within the cylinder chamber 42 is exhausted through the hollow piston rod I1, to the chamber 4 I', through the pipe 40, through the port 39, into the valve chamber 38, and passes out through the pipe 49, through the V-port in the speed control valve 5|, and exhausts through the pipe 54 into the reservoir 2|. The valve 5| serves to control the rate of exhaust of uidand thereby to control and regulate the speed of movement of the table H.

The table continues its movement toward the right until the reversing dog 92 engages ,the stud 3|, after which continued movement of the table toward the right shifts the reversing lever in a .clockwise direction from position 85h toward position 85a. `When the slidably mounted reversing valve member 32 reaches its extreme righthand end position, as indicated in Fig. 7, the continued influence of fluid under pressure within the valve chamber |30 shifts the Valve piston 23 and its associated parts toward the left into the position illustrated in Fig. '7. During the initial shifting movement of the lever 85 from position 85h in a clockwise direction, the valve stem 28 is shifted toward the left together with the slidably mounted reversing valve member 32. fThe initial movement of the valve parts is under the influence of the table as transmitted through the reversing lever 85. This movement of the valve parts is continued until the valve piston 34 shifts toward the left from the position illustrated in Fig. 7 to close the exhaust port 43, thus stopping the exhaust of fluid from'the cylinder chamber 42. When the valve parts reach this position, the port iti is opened so that fluid within the valve chamber |00 may pass into the reservoir |02. The valve parts have also moved sumciently toward the left so that the valve piston 35 has uncovered the port |06, thus admitting uid under pressure into the valve'chamber |05. The

admission of fluid into the chamber |05 acting upon the valve piston 35 serves to rapidly and positively shift the slidably mounted reversing valve member 32 toward the left under the influence of uid under pressure into its extreme lefthand end position, as illustrated in Fig. 3, in which position the uid flow is reversed and fluid under pressure conveyed in a manner herein= above described to the cylinder chamber 42 to cause the table to start its movement toward the left. Fluid under pressure entering the valve chamber |05 then shifts the valve piston 30 toward the' right so that the valve parts again assume the positions illustrated in Fig. 3.

If it is desired' to stop the reciprocatory movement ofthe table the control lever 65 may be shifted in a clockwise direction into position 65a. This movement serves to shift the valve piston 57 to close the V-port 59, thus cutting off exhaust of uid from the table cylinder |2 to stop the table movement. When the valve 5| is in a stop position, the pipe is directly connected with the pipe 8| through a valve chamber 82 which is then positioned in position 82a shown in broken lines in Fig. 1, so that uid may readily by-pass between the cylindervchamber I2 and the cylinder chamber 43 to facilitate a manual traversing movement of the table Il.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together chambers, one or said ports being opened during e reversal at each end of the table stroke to admit with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of .the above invention and fluid under pressure directly from said source to one of said chambers positively and rapidly to shift said reversing valve independently of said valve member into a reverse position.

3. In a hydraulically operated table traversing mechanism including a piston and cylinder, a

l source of fluid under pressure, a reversing valve as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim: Y

1. In a hydraulically operated table reciprocating mechanism including a piston and cylinder, a source ofuid under pressure, a piston type reversing valve comprising a casing, a slidably mounted valve member therein having a pair oi spaced valve pistons thereon, a reversing valve slidably supported on said member having a plurality of spaced integrally formed pistons, the

movement of said reversing valve in either direction being limited by said casing, the effective areas of the reversing valve pistons being greater than the effective areas of the spaced valve pistons on said valve member, a valve chamber formed at each end of the reversing valve between the reversing valve and said spaced valve pistons, respectively, table actuated means to shift said valve member and said reversing valve to shift the reversing valve to -a central position, and a valve port for each of said chambers successively connecting a source of iluid under pressure with said valve chambers, one of said ports being opened during reversal at each end of the table stroke to admit fluid under pressure directly from said source to one of said chambers positively and rapidly to shift the reversing valve so as to reverse the ow of iluid under pressure to said cylinder after which, due to the effective area of the reversing valve piston, fluid under pressure -in'the end chamber will shift both the reversing valve and the slidably mounted valve member into the extreme reverse position.

2. In a hydraulically operated table reciprocating mechanism including a piston and cylinder, a source of fluid under pressure, a piston type reversing valve comprising a slidably mounted valve member having a pair of spaced valve pistons thereon, a reversing valve slidably supported on said member having a plurality of spaced integrally formed pistons, the eil'ective areas of the reversing valve pistons being greater than the effective areas of the spaced valve pistons on said valve member, a valve chamber formed at each end of the reversing valve between the reversing valve and said spaced valve pistons, respectively, table actuated means to shift said valve member and said reversing valve to shift the reversing valve to a central position, and a valve port for each of said chambers successively connecting a source of uid under pressure with said valve able table dogs to shift said valve member and i therefor including a valve casing, a valve member having a pair of spaced valve pistons slidably mounted within said casing, a reversing valve member slidably supported in said casing and slidable relative to said valve member and having a plurality of spaced integrally formed valve pistons thereon, the eifective areas of the reversing valve pistons being greater than the effective areas of the spaced valve pistons on said valve member, a valve chamber formed at each end of the reversing valve between the reversing valve and said spaced valve pistons on said valve member, respectively, a reversing lever and adjustsaid reversing valve to shift the reversing valve to a central position, and a port opened during said movement to admit fluid under pressure directly from the source to one of said chambers positively and rapidly to shift the reversing valve independently of said valve member into a reverse position so as to reverse the nmovement of said tame.

4. In a hydraulically operated table reciprocating mechanism including a piston and cylinder, a source of fluid under pressure, a piston type reversing valve comprising a casing and a slidably mounted reversing valve member having a plurality of integrally formed pistons thereon which are arranged to reverse the iow of fluid under pressure to a ta-ble cylinder, the movement of the reversing valve member in either direction being limited by said casing, a slidablymounted valve member having a portion slidable within the reversing valve member, spaced valve pistons on said said second valve member which are spacedv and independently to shift the reversing valve member so as to reverse the flow of fluid under pressure to said cylinder after which, due to the eil'ective area of the reversing valve piston, fluid 4under pressure in the end chamber will shift both the reversing valve and the slidably mounted valve member into the extreme reverse position.

CARL G. FLYGARE. 

